Dog whistle



FIG. 1 is a top perspective view showing our design;

FIG. 2 is a bottom perspective view;

FIG. 3 is a front view;

FIG. 4 is a rear view;

FIG. 5 is a left side view;

FIG. 6 is a right side view;

FIG. 7 is a top view; and,

FIG. 8 is a bottom plan view thereof.

CLAIM The ornamental design for a dog whistle, as shown and described.